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Yuan J, Liu Z, Han T, Li J, Han P, Wang J. Preparation and Molecular Dynamic Simulation of Superfine CL-20/TNT Cocrystal Based on the Opposite Spray Method. Int J Mol Sci 2024; 25:9501. [PMID: 39273448 PMCID: PMC11395131 DOI: 10.3390/ijms25179501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2024] [Revised: 08/24/2024] [Accepted: 08/28/2024] [Indexed: 09/15/2024] Open
Abstract
In view of the current problems of slow crystallization rate, varying grain sizes, complex process conditions, and low safety in the preparation of CL-20/TNT cocrystal explosives in the laboratory, an opposite spray crystallization method is provided to quickly prepare ultrafine explosive cocrystal particles. CL-20/TNT cocrystal explosive was prepared using this method, and the obtained cocrystal samples were characterized by electron microscopy morphology, differential thermal analysis, infrared spectroscopy, and X-ray diffraction analysis. The effects of spray temperature, feed ratio, and preparation method on the formation of explosive cocrystal were studied, and the process conditions of the pneumatic atomization spray crystallization method were optimized. The crystal plane binding energy and molecular interaction forces between CL-20 and TNT were obtained through molecular dynamic simulation, and the optimal binding crystal plane and cocrystal mechanism were analyzed. The theoretical calculation temperature of the binding energy was preliminarily explored in relation to the preparation process temperature of cocrystal explosives. The mechanical sensitivity of ultrafine CL-20/TNT cocrystal samples was tested. The results showed that choosing acetone as the cosolvent, a spraying temperature of 30 °C, and a feeding ratio of 1:1 was beneficial for the formation and growth of cocrystal. The prepared CL-20/TNT cocrystal has a particle size of approximately 10 μm. The grain size is small, and the crystallization rate is fast. The impact and friction sensitivity of ultrafine CL-20/TNT cocrystal samples were significantly reduced. The experimental process conditions are simple and easy to control, and the safety of the preparation process is high, providing certain technical support for the preparation of high-quality cocrystal explosives.
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Affiliation(s)
- Junming Yuan
- School of Environmental and Safety Engineering, North University of China, Taiyuan 030051, China
| | - Zhenyang Liu
- School of Environmental and Safety Engineering, North University of China, Taiyuan 030051, China
| | - Tao Han
- School of Environmental and Safety Engineering, North University of China, Taiyuan 030051, China
| | - Junyi Li
- School of Environmental and Safety Engineering, North University of China, Taiyuan 030051, China
| | - Peijiang Han
- School of Environmental and Safety Engineering, North University of China, Taiyuan 030051, China
| | - Jing Wang
- School of Environmental and Safety Engineering, North University of China, Taiyuan 030051, China
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2
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Wu S, Lu Z, Bai L. Mechanical behaviors of CL-20 under an impact loading: A molecular dynamics study. J Mol Graph Model 2024; 129:108733. [PMID: 38412812 DOI: 10.1016/j.jmgm.2024.108733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/24/2024] [Accepted: 02/15/2024] [Indexed: 02/29/2024]
Abstract
Study on the dynamic process of CL-20 crystal under impact is critical for the safe utilization of energetic materials under extreme conditions. Herein, the mechanical and structural evolution of CL-20 under the impact of a diamond ball is investigated by using molecular dynamics simulation. The considerations are given to the effect of different impact velocity, impact direction and impact angle. It is found that a high impact velocity results in a large indentation depth and force, as well as more significant energy transition and the formation of a large number of molecular fragments. Moreover, CL-20 exhibits weak anisotropy along different impact directions due to the crystalline distribution anisotropy. Furthermore, the mechanical response of CL-20 is angle-dependent, which is caused by the discrepancy in local molecular re-arrangement. These results may enhance the understanding of the mechanical behavior of CL-20 and promote its wide applications.
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Affiliation(s)
- Shuang Wu
- Key Laboratory of Traffic Safety on Track (Central South University), Ministry of Education, School of Traffic & Transportation Engineering, Central South University, Changsha, 410075, China
| | - Zhaijun Lu
- Key Laboratory of Traffic Safety on Track (Central South University), Ministry of Education, School of Traffic & Transportation Engineering, Central South University, Changsha, 410075, China.
| | - Lichun Bai
- Key Laboratory of Traffic Safety on Track (Central South University), Ministry of Education, School of Traffic & Transportation Engineering, Central South University, Changsha, 410075, China
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Sun Z, Ji J, Zhu W. Effects of Nanoparticle Size on the Thermal Decomposition Mechanisms of 3,5-Diamino-6-hydroxy-2-oxide-4-nitropyrimidone through ReaxFF Large-Scale Molecular Dynamics Simulations. Molecules 2023; 29:56. [PMID: 38202639 PMCID: PMC10779735 DOI: 10.3390/molecules29010056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 12/16/2023] [Accepted: 12/17/2023] [Indexed: 01/12/2024] Open
Abstract
ReaxFF-lg molecular dynamics method was employed to simulate the decomposition processes of IHEM-1 nanoparticles at high temperatures. The findings indicate that the initial decomposition paths of the nanoparticles with different sizes at varying temperatures are similar, where the bimolecular polymerization reaction occurred first. Particle size has little effect on the initial decomposition pathway, whereas there are differences in the numbers of the species during the decomposition and their evolution trends. The formation of the hydroxyl radicals is the dominant decomposition mechanism with the highest reaction frequency. The degradation rate of the IHEM-1 molecules gradually increases with the increasing temperature. The IHEM-1 nanoparticles with smaller sizes exhibit greater decomposition rate constants. The activation energies for the decomposition are lower than the reported experimental values of bulk explosives, which suggests a higher sensitivity.
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Affiliation(s)
- Zijian Sun
- Institute for Computation in Molecular and Materials Science, School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
| | - Jincheng Ji
- College of Chemical Engineering and Pharmacy, Jingchu University of Technology, Jingmen 448000, China;
| | - Weihua Zhu
- Institute for Computation in Molecular and Materials Science, School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;
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Zhang J, Guo W, Yao Y. Deep Potential Molecular Dynamics Study of Chapman-Jouguet Detonation Events of Energetic Materials. J Phys Chem Lett 2023; 14:7141-7148. [PMID: 37535980 DOI: 10.1021/acs.jpclett.3c01392] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
Detonation of energetic materials (EMs) is of great importance for military applications, while the understanding of detailed events and mechanisms for the detonation process is scarce. In this study, the first deep neural network potential NNP_Shock for molecular dynamics (MD) simulation of shock-induced detonation of EMs was generated based on a deep potential model, providing DFT accuracy but 106 times the computational efficiency. On this basis, we employ our deep potential to perform MD simulations of shock-induced detonation of high-performance EM material 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20, C6H6N12O12) and obtain the theoretical Chapman-Jouguet (C-J) detonation velocities and pressures directly by multiscale shock technique (MSST) for the first time, which are in good agreement with experiment. In addition, the Hugoniot curves and initial reaction mechanisms were successfully obtained. Therefore, the NNP_Shock potential is competent in research of the detonation performance and shock sensitivity of CL-20, and the method can also be transplanted to studies of other EMs.
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Affiliation(s)
- Jidong Zhang
- College of Sciences/Xinjiang Production & Construction Corps Key Laboratory of Advanced Energy Storage Materials and Technology, Shihezi University, Shihezi 832000, China
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, P. R. China
| | - Wei Guo
- Frontiers Science Center for High Energy Material (MOE), Beijing Institute of Technology, Beijing 100081, P. R. China
- School of Physics, Beijing Institute of Technology, Beijing 100081, P. R. China
| | - Yugui Yao
- Frontiers Science Center for High Energy Material (MOE), Beijing Institute of Technology, Beijing 100081, P. R. China
- School of Physics, Beijing Institute of Technology, Beijing 100081, P. R. China
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China
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5
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Sun X, Liang W, Li X, Mai D, Zhang Y, Sui Z, Dai R, Zheng X, Wang Z, Duan X, Zhang Z. Structural evolution of CL-20/DNB cocrystals at high temperature: Phase transition and kinetics of thermal decomposition. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 292:122436. [PMID: 36753867 DOI: 10.1016/j.saa.2023.122436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/20/2023] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
As a typical new energetic material, CL-20/DNB cocrystals have been recognized as a promising explosive owing to their excellent comprehensive performance. The thermal decomposition behavior, structural evolution and dynamic process of CL-20/DNB cocrystals under high temperature were studied by means of thermogravimetric differential heating, X-ray diffraction, Raman spectroscopy to gain insight into the cocrystal materials. The study found that the decomposition of CL-20/DNB cocrystal is a heterogeneous process accompanied by the sublimation of DNB and structural change of CL-20. The phase transition of β → γ-CL-20 was observed at 120 °C. The kinetics of decomposition and the mechanism of micro structural evolution on CL-20/DNB cocrystals with heating were revealed. The primary NO⋯H hydrogen bonds of the cocrystal are broken, accompanied by the melting of DNB in the temperature range of 100-120 °C. Subsequently, the DNB single component decomposes completely, leading to lattice collapse of cocrystal; simultaneously, CL-20 undergoes a transition process from β phase to γ phase. Ultimately, γ-CL-20 gradually decomposes with increasing temperature. The activation energy of cocrystal is also obtained as 129 ± 10 kJ/mol. The understanding of cocrystal explosive was deepened and the further application was promoted.
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Affiliation(s)
- Xiaoyu Sun
- The Center for Physical Experiments, School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Wentao Liang
- Department of Physics, School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Xiangdong Li
- Department of Physics, School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Di Mai
- Department of Physics, School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yang Zhang
- Department of Physics, School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zhilei Sui
- Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China
| | - Rucheng Dai
- The Center for Physical Experiments, School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xianxu Zheng
- Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan 621900, China
| | - Zhongping Wang
- The Center for Physical Experiments, School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
| | - Xiaohui Duan
- Key Laboratory of Environment-friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, China.
| | - Zengming Zhang
- The Center for Physical Experiments, School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
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Wang F, Du G, Zhang C, Wang QY. Mechanism of the Impact-Sensitivity Reduction of Energetic CL-20/TNT Cocrystals: A Nonequilibrium Molecular Dynamics Study. Polymers (Basel) 2023; 15:polym15061576. [PMID: 36987360 PMCID: PMC10057516 DOI: 10.3390/polym15061576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/07/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
High-energy low-sensitivity explosives are research objectives in the field of energetic materials, and the formation of cocrystals is an important method to improve the safety of explosives. However, the sensitivity reduction mechanism of cocrystal explosives is still unclear. In this study, CL-20/TNT, CL-20 and TNT crystals were taken as research objects. On the basis of the ReaxFF-lg reactive force field, the propagation process of the wave front in the crystals at different impact velocities was simulated. The molecular dynamics data were used to analyze the molecular structure changes and initial chemical reactions, and to explore the sensitivity reduction mechanism of the CL-20/TNT cocrystal. The results showed that the chemical reaction of the CL-20/TNT cocrystal, compared with the CL-20 single crystal, is different under different impact velocities. At an impact velocity of 2 km/s, polymerization and separation of the component molecules weakened the decomposition of CL-20. At an impact velocity of 3 km/s, the decay rates of CL-20 and TNT in the cocrystal decreased, and the intermediate products were enhanced, such as nitrogen oxides. At an impact velocity of 4 km/s, the cocrystal had little effect on the decay rates of the molecules and formation of CO2, but it enhanced formation of N2 and H2O. This may explain the reason for the impact-sensitivity reduction of the CL-20/TNT cocrystal.
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Affiliation(s)
- Fuping Wang
- Department of Chemistry and Material Science, Langfang Normal University, Langfang 065000, China
| | - Guangyan Du
- Department of Chemistry and Material Science, Langfang Normal University, Langfang 065000, China
| | - Chenggen Zhang
- Department of Chemistry and Material Science, Langfang Normal University, Langfang 065000, China
| | - Qian-You Wang
- Henan Key Laboratory of Crystalline Molecular Functional Materials, Green Catalysis Center and College of Chemistry, Zhengzhou University, Zhengzhou 450001, China
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Gao C, Li X, Wang J, Sun X, Liu S, Zhang Z. Molecular conformation evolutions of trans HNS under high pressure. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 286:121994. [PMID: 36283205 DOI: 10.1016/j.saa.2022.121994] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/27/2022] [Accepted: 10/12/2022] [Indexed: 06/16/2023]
Abstract
The molecular conformation evolution of Hexanitrostilbene (HNS) under high pressure was systematically investigated using Raman and Fourier transform infrared (FTIR) spectroscopy. The vibration modes of HNS associated with C-H, nitro groups, CC and the ring have been analyzed and clarified in detail under ambient conditions. trans-HNS is symmetrically distributed about -CHCH-, and six nitro groups are symmetrically distributed under ambient conditions. Two molecular conformation changes of HNS were observed at 1.4 GPa and 5 GPa due to the variations of hydrogen-bond interaction between C-H (in the ring) and N-O and the distortion of trans olefin, respectively. The hydrogen-bond interaction between C-H (in the ring) and N-O strengthened at 1.4 GPa. It induced the degenerated symmetry of the nitro groups and the Raman changes of νas (NO2), ν(CC), ν(C-C) and ν(C-H). In addition, the nonplanarity property of HNS and the sensitivity of trans olefin to pressure promoted the deformation of trans olefin, as well as the hydrogen bond interaction between C-H (in trans olefin) and N-O at about 5 GPa. When further loading pressure on HNS, the variations in the hydrogen-bond interaction between C-H and N-O restricted the vibrations of C-H, NO2 and the ring. It blocked the nonradiative pathway and activated the strong fluorescent background in the Raman spectra as the pressure increased above 5.7 GPa. These current results reveal that there is no structural transformation and only conformational changes under high pressure for HNS.
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Affiliation(s)
- Chan Gao
- College of Mathematics and Physics, Chengdu University of Technology, Chengdu, Sichuan 610059, China.
| | - Xiangdong Li
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Junke Wang
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiaoyu Sun
- The Centre for Physical Experiments, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shuang Liu
- College of Mathematics and Physics, Chengdu University of Technology, Chengdu, Sichuan 610059, China
| | - Zengming Zhang
- The Centre for Physical Experiments, University of Science and Technology of China, Hefei, Anhui 230026, China; Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.
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8
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Quansah J, Zhang X, Wasiullah Q, Yan QL. Mechanical and Thermophysical Properties of Energetic Crystals: Evaluation Methods and Recent Achievements. FIREPHYSCHEM 2022. [DOI: 10.1016/j.fpc.2022.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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9
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Li Y, Yu WL, Huang H. CL-20/TNT decomposition under shock: cocrystalline versus amorphous. RSC Adv 2022; 12:6938-6946. [PMID: 35424606 PMCID: PMC8982055 DOI: 10.1039/d1ra09120d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/24/2022] [Indexed: 11/21/2022] Open
Abstract
The cocrystallization strategy is considered to be an effective means to adjust the properties of explosives. Nevertheless, the underlying mechanism of the effect of the special cocrystal structure on the decomposition process is not clear enough. The present work compares the response processes of a CL-20/TNT cocrystal structure and an amorphous structure under shock waves with different velocities. The thermodynamic evolution, reactant decay, product formation, main initial reactions and cluster evolution are analyzed. As a result, we find that the amorphous structure is easier to compress than the cocrystal structure, achieving higher stress and temperature. These thermodynamic parameters have a strong correlation. For the amorphous structure, the chemical reaction of the system is more intense, the reactants decay faster, the products are more abundant, and the intermediate products can complete the transformation to stable products earlier. Furthermore, NO2 is the most important intermediate product, and its quantitative change can directly reflect the reaction process. The amorphous structure is more prone to decomposition reaction, and the cocrystal structure is more prone to polymerization reaction. The cluster size in the amorphous structure is smaller and more conducive to decomposition.
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Affiliation(s)
- Yan Li
- Xi'an High-Tech Research Institute Xi'an 710025 China
- Naval University of Engineering Wuhan 430033 China
| | - Wen-Li Yu
- Xi'an High-Tech Research Institute Xi'an 710025 China
| | - Huang Huang
- Naval University of Engineering Wuhan 430033 China
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Zhang J, Guo W. The role of electric field on decomposition of CL-20/HMX cocrystal: A reactive molecular dynamics study. J Comput Chem 2021; 42:2202-2212. [PMID: 34476813 DOI: 10.1002/jcc.26748] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/11/2021] [Accepted: 08/18/2021] [Indexed: 11/10/2022]
Abstract
Electric field can initiate decomposition or detonation of explosives, but underlying mechanism is unclear. Here, we performed ReaxFF molecular dynamics simulation for decomposition of a cocrystal, formed by 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX), solely induced by electric field. A new analytical method was proposed to obtain detailed decomposition mechanism. Results show that electric fields play important roles in decomposition of CL-20/HMX cocrystal, such as heating the system and causing the explosive to decompose. Strong constant field makes CL-20 molecules in the cocrystal decompose at significantly lower temperature, which greatly increases sensitivity. This is ascribed to the distinct decomposition mechanism that CN bond rupture dominates the initial step of CL-20's decomposition. Contrarily, oscillating field has a stronger heating effect but weaker influence on sensitivity. Moreover, HMX exhibits desensitizing effect in CL-20/HMX cocrystal under electric field. These results enhance our understanding of sensitivity mechanism beyond mechanical stimuli in explosives.
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Affiliation(s)
- Jidong Zhang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China.,Key Laboratory of Ecophysics and Department of Physics, College of Science, Shihezi University, Shihezi, China
| | - Wei Guo
- Frontiers Science Center for High Energy Material (MOE), Beijing Institute of Technology, Beijing, China.,School of Physics, Beijing Institute of Technology, Beijing, China
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Xiao Y, Chen L, Geng D, Yang K, Lu J, Wu J. A quantum-based molecular dynamics study of the ICM-102/HNO 3 host-guest reaction at high temperatures. Phys Chem Chem Phys 2020; 22:27002-27012. [PMID: 33210682 DOI: 10.1039/d0cp04511j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The contradiction between energy and safety of explosives is better balanced by the host-guest inclusion strategy. Understanding the reaction mechanism of the host-guest explosive is necessary. To deeply analyze the role of the small guest molecules in the host-guest system, a quantum-based molecular dynamics method was used to calculate the initial decomposition reaction of the new host-guest explosive ICM-102/HNO3 against the pure ICM-102 at several high temperatures. The incorporation of HNO3 had no significant influence on the initial decomposition step of ICM-102. Conversely, the earliest intramolecular hydrogen transfer reaction is delayed partly because the H and O atoms of HNO3 connect with the O and H atoms of ICM-102, respectively. As the reaction proceeds, guest molecules get heavily involved in the reaction and increase the reaction rate. The generation rate and quantity of the small oxidizing molecules in the final product were increased significantly in the ICM-102/HNO3 system. These mechanisms revealed that HNO3 molecules inhibit the early stages of the initial decomposition of ICM-102 to some extent, and play an important role in accelerating the decomposition subsequently.
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Affiliation(s)
- Yiwen Xiao
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China.
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12
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Ren C, Liu H, Li X, Guo L. Decomposition mechanism scenarios of CL-20 co-crystals revealed by ReaxFF molecular dynamics: similarities and differences. Phys Chem Chem Phys 2020; 22:2827-2840. [PMID: 31965130 DOI: 10.1039/c9cp06102a] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Understanding the similarities and differences of decomposition mechanisms of CL-20 and its cocrystals is of great interest for practical applications of CL-20 cocrystals. The responses of CL-20 cocrystals to thermal stimulus were investigated using ReaxFF molecular dynamics simulations of two representative cocrystals, CL-20/HMX and CL-20/TNT, under adiabatic conditions and comparing to the baseline system of pure CL-20. The comprehensive chemical details were revealed with the aid of the unique code of VARxMD. The three CL-20-involved reactive systems all exhibit a distinct three-stage character during adiabatic decomposition when using the double peaks of the major intermediate NO2 amount as the boundary. By taking advantage of the three-stage classification, a clear scenario for the similar stimulus-response of the CL-20 cocrystals can be elucidated for the dominant primary decomposition of CL-20 in stage I and the transition of favored chemical mechanisms from the generation of intermediates/radicals in stage II into their consumption to form stable products in stage III. The similar chemical behaviors are rooted in the dominance of CL-20 chemistry in the initial response of its cocrystals to thermal stimulus. The prolonged reaction zone uncovers the slowed decomposition kinetics of CL-20/HMX and CL-20/TNT, which is associated with the altered kinetics of CL-20 decomposition specifically by N-NO2 bond scission and CL-20 skeleton decay. The retarded CL-20 decomposition in its cocrystals consequently results in more moderate self-heating and less violent exothermic reactions that agrees with the experimental observations of improved stability and damaged detonation performance of CL-20 cocrystals, particularly for CL-20/TNT. The results obtained in this work suggest that ReaxFF MD simulations can provide useful insight for the modulated chemical properties of varied CL-20 cocrystals.
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Affiliation(s)
- Chunxing Ren
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China. and University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Han Liu
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China. and University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xiaoxia Li
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China. and University of Chinese Academy of Sciences, Beijing 100049, P. R. China and Innovation Academy for Green Manufacture, Chinese Academy of Sciences, P. R. China
| | - Li Guo
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China. and University of Chinese Academy of Sciences, Beijing 100049, P. R. China and Innovation Academy for Green Manufacture, Chinese Academy of Sciences, P. R. China
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Sun S, Zhang H, Xu J, Wang H, Wang S, Yu Z, Zhu C, Sun J. Design, preparation, characterization and formation mechanism of a novel kinetic CL-20-based cocrystal. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2019; 75:310-317. [PMID: 32830652 DOI: 10.1107/s2052520619002816] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 02/24/2019] [Indexed: 06/11/2023]
Abstract
2,4,6,8,10,12-Hexanitrohexaazaisowurtzitane (CL-20)-based cocrystals have gained increasing attention as a means of obtaining insensitive high explosives. However, the design of ideal candidates for these cocrystals remains difficult. This work compares the crystal energies of the CL-20-dinitrobenzene (DNB) and CL-20-2,4,6-trinitrotoluene (TNT) cocrystals with those of the respective pure coformers. The results indicate that the cocrystal formation is driven by the differences in the energies of the cocrystals and the coformers. Furthermore, analysis via Hirshfeld surfaces and two-dimensional fingerprint plots confirms that the O...O, O...H, O...N and C...O interactions were the main force for stabilizing the CL-20-based cocrystal structure. Based on these findings, a novel energetic-energetic cocrystal of CL-20-2,4,6-trinitrophenol (TNP) was designed and prepared by means of a rapid method for solvent removal. The crystal structure was investigated via powder X-ray diffraction methods, solid-state nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. The results revealed that the O-H...O hydrogen bonding interaction between the phenolic hydroxyl group of TNP and nitro groups of CL-20, as well as nitro...π, nitro...nitro and ONO2...π(N)NO2 interactions, based on the benzene ring and nitro groups, are the main interactions occurring in the cocrystal.
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Affiliation(s)
- Shanhu Sun
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, Sichuan, People's Republic of China
| | - Haobin Zhang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, Sichuan, People's Republic of China
| | - Jinjiang Xu
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, Sichuan, People's Republic of China
| | - Hongfan Wang
- School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan, People's Republic of China
| | - Shumin Wang
- School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan, People's Republic of China
| | - Zhihui Yu
- School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan, People's Republic of China
| | - Chunhua Zhu
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, Sichuan, People's Republic of China
| | - Jie Sun
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang 621900, Sichuan, People's Republic of China
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Ren C, Li X, Guo L. Chemical Insight on Decreased Sensitivity of CL-20/TNT Cocrystal Revealed by ReaxFF MD Simulations. J Chem Inf Model 2019; 59:2079-2092. [DOI: 10.1021/acs.jcim.8b00952] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Chunxing Ren
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Xiaoxia Li
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Li Guo
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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